Harvesting Costs forManagement Planning forPonderosa Pine PlantationsRoger D. Fight, Alex Gicqueau, andBruce R. Hartsough

United States Department ofAgriculture

Forest Service

Pacific NorthwestResearch Station

General TechnicalReportPNW-GTR-467June 1999

Authors ROGER D. FIGHT is a principal economist, U.S. Department of Agriculture, ForestService, Pacific Northwest Research Station, P.O. Box 3890, Portland, OR 97208-3890; and ALEX GICQUEAU was a graduate student and BRUCE R. HARTSOUGHis a professor, University of California, Department of Biological and AgriculturalEngineering, Davis, CA 95616-5294. Gicqueau is currently a senior software devel-oper, Axolotl Corp., Cupertino, CA 95014.

Abstract Fight, Roger D.; Gicqueau, Alex; Hartsough, Bruce R. 1999. Harvesting costs for management planning for ponderosa pine plantations. Gen. Tech. Rep. PNW-GTR-467. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 8 p.

The PPHARVST computer application is Windows-based, public-domain software usedto estimate harvesting costs for management planning for ponderosa pine (Pinusponderosa Dougl. ex Laws.) plantations. The equipment production rates were devel-oped from existing studies. Equipment cost rates were based on 1996 prices for newequipment. Harvesting systems include a cut-to-length harvester-forwarder system, awhole-tree/log-length skidder system, and a skyline cable system. Harvesting costscan be estimated for both clearcutting and partial cutting for trees ranging from 3cubic feet to 250 cubic feet. Cost estimates are in U.S. dollars per 100 cubic feet.

Keywords: Costs (logging), logging economics, timber management planning, young-growth stands, ponderosa pine.

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Introduction An important factor in plantation management planning is the effect of silviculturaldecisions on the cost of harvesting. It is generally more costly to harvest smallerdiameter trees than larger diameter trees and more costly to harvest lower volumesper acre than higher volumes per acre. The cost penalties for low volumes per acreand small trees differ among types of logging systems; for example, harvesting with acable system is typically more expensive than with a mechanized system, and theincremental penalties of increasing costs also are greater when lower volumes peracre or smaller trees are harvested. It is therefore appropriate to consider, at the timethe silvicultural prescription is developed, the type of harvesting system likely to beused in a stand. With that system in mind, harvest costs can be estimated that willindicate the effect of different management strategies on harvesting costs and totalfinancial return. If logging cost relations are ignored, prescriptions may be developedthat call for early thinning or frequent light thinning, which will reduce the overallvalue of the regime, or cause the cost of the harvest to be more than the timber isworth. Even on those lands where financial return from timber may not be the primarygoal, it is important to know that the costs of the anticipated regime are such that it isfeasible to implement the prescription.

The PPHARVST application was specifically developed for use in exploring optimal silvi-cultural regimes for ponderosa pine (Pinus ponderosa Dougl. ex Laws.) plantations.Realistic harvesting costs over a wide range of stand conditions are essential forsuch an application because optimizing algorithms search more-or-less all possiblecombinations of treatments. Some combination that ordinarily would not even be con-sidered practical might be judged optimal if inappropriate costs are used. We havetaken care to develop cost relations that are sensitive to the stand variables that aredirectly affected by silvicultural decisions and have a significant impact on harvestingcosts. The two most important variables determined by manipulation of stocking andharvest age are the number of trees per acre harvested and the average volume pertree for each harvest entry.

The purpose of this paper is to describe PPHARVST and how it can be used to estimatethe cost of harvesting ponderosa pine plantations over a wide range of tree sizes andvolumes removed by three types of harvesting systems: a cable yarding system, aground-based cut-to-length harvesting system, and a ground-based whole-tree/log-length harvesting system (hereafter referred to as a “whole-tree system”). Enoughinformation is included to provide a clear understanding of the system configurationand situation being simulated. It was not our intent to provide the information neededto determine whether a particular system is appropriate for a particular situation. It ispresumed that the user will get the technical and policy information needed to makethat decision. The PPHARVST software, this document, and related documents can beaccessed from the Internet at http://www.fs.fed.us/pnw.

The production rates on which the model is based are drawn from the existing litera-ture. These sources, resulting equations, and costing approach are described indetail in Hartsough and others (1998). The capital and operating costs on which themodel is based were developed by use of a standard machine cost approach withreplacement purchase prices for new equivalent equipment. Equipment prices werefor January 1996. Those interested in the detailed assumptions have access to themthrough the software and can change them if they wish.

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Description ofPPHARVST andRequirements

Harvesting Systemsand Conditions

The PPHARVST application was developed for a Windows 95 operating system.1 APPHARVST exercise typically involves specifying a logging system, whether it is a par-tial cut or clearcut, the average slope yarding distance, slope, move-in distance, andthe number of acres being harvested at that location. Results are shown for a user-specified range of tree sizes in cubic feet and range of numbers of harvested treesper acre. The resulting table of costs would then be an appropriate estimate of costfor a single harvest, a series of harvests that might occur in a stand, or the cost foralternative harvests or stands. Figure 1 is an abbreviated example of such a tableand the key assumptions on which the table is based.

The model provides cost estimates for two systems on gentle terrain and one systemon steep terrain for both partial cutting and clearcutting. The following tabulation sum-marizes the circumstances covered:

Item Harvest parameters

Terrain Gentle Gentle Steep System Whole-tree Cut-to-length Cable Tree size (cubic feet) 3-250 3-150 3-250 Harvest type Partial cut Clearcut Partial cut Clearcut Partial cut Clearcut

1 The use of trade or firm names in this publication is for readerinformation and does not imply endorsement by the U.S. Depart-ment of Agriculture of any product or service.

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Figure 1—Screen showing PPHARVST input values and results.

Gentle Terrain Systems

For the whole-tree and the cut-to-length systems, the equipment components are thesame for partial cutting and clearcutting but differ with tree size. For the yarding sys-tem, a smaller yarder is used for partial cutting than for clearcutting. With the excep-tion of the yarding system for partial cutting, each system has one configuration forsmall trees and one for large trees. The resulting production relations and costs weredeveloped by blending the proportions of the two configurations. The blendingprocess is explained below.

The whole-tree system for smaller trees consists of a feller-buncher, a skidder, astroke processor, and a loader; for larger trees, it consists of chainsaw felling andprocessing, a skidder, and a loader. For harvests with average tree size of less than80 cubic feet, the cost is based 100 percent on the feller-buncher system. For har-vests with average tree size of greater than 150 cubic feet, the cost is based 100percent on the chainsaw felling system. If average tree size is between 80 and 150cubic feet, the cost is a weighted average of the two systems; i.e., if average treesize is halfway between 80 and 150 cubic feet the cost is a 50:50 weighting of thetwo systems. Figure 2 shows how the proportions of the two systems differ with treesize. (We are not suggesting that these systems be used in combination in any givenharvesting operation.) The logic of this approach is that the two configurations repre-sent but two choices from a continuum of configurations actually used, and thisblending of costs approximates the gradual shift to heavier equipment that tends tooccur as tree size increases. The other systems are blended similarly. Details on theblending for all systems are found in Hartsough and others (1998).

The cut-to-length system for smaller trees consists of a small harvester, a forwarder,and a loader; for larger trees, it consists of a feller-buncher, a stroke processor, a forwarder, and a loader.

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Figure 2—Harvesting cost is a weighted average based on proportionof volume harvested by two configurations going from 0 percent chainsaw felling for trees under 80 cubic feet to 100 percent chainsawfelling for trees over 150 cubic feet.

How To Get StartedWith PPHARVST

Installing PPHARVST on a Hard Drive

Entering Data IntoPPHARVST

The steep terrain system is a cable yarding system. For partial cutting, it consists of chainsaw felling, a small mobile yarder, and a loader. The yarding system forclearcutting of smaller trees consists of chainsaw felling, an intermediate-sized mobileyarder, and a loader; for larger trees, it consists of a combination of the same systemas for smaller trees and a system consisting of chainsaw felling, a large tower yarder,and a loader.

PPHARVST runs under Windows 95/NT/98. It produces a table of harvesting costs indollars per 100 cubic feet (US$/cunit) for ponderosa pine plantations, over a range oftree sizes (cubic feet per tree) and number of trees cut (trees per acre). The harvest-ing conditions are chosen by the user by selecting options on the program resultsscreen. The screen resembles a spreadsheet.

The application was first created as an Excel spreadsheet. It was than converted to astand-alone program by use of Visual Basic and Formula One. All the calculation rou-tines are available to the user through the Formula One Workbook Designer (doubleright-click within the spreadsheet portion of the program window) or as an Excelspreadsheet (open any saved spreadsheet in Excel). No software beyond PPHARVST

itself is necessary to use the program.

Although PPHARVST does not require a spreadsheet program, it requires some dynam-ic link library files and other files that may not be available on all personal computersytems. Some of these are supplied with Visual Basic or Formula One; however, theymay be distributed without charge. To install PPHARVST and the required files, executethe setupex.exe file that you downloaded from the PPHARVST web page and follow theinstructions in the setup program. The files will be transferred to the appropriate sub-directories on the hard disk, and a PPHARVST program icon will be created.

Double-click on the PPHARVST icon that shows up in Program Manager. The programresults screen will appear (fig. 3). The following four steps are required.

1. Click on the top left combo box to select the type of harvesting system: wholetree, cut-to-length, or yarding.

2. In the next box below, select the type of harvest: clearcut or partial cut.

3. In the fifth row in the spreadsheet area, enter an array of tree sizes, each in cubicfeet, beginning in cell C5. Any number of tree sizes may be entered, but no cellwithin the range should be left blank because results for entries beyond a blankcell will not be calculated. Tree sizes must be within the range of 3 to 250 cubicfeet (3 to 150 for the cut-to-length system). The tree sizes can be of any valuewithin the valid range; they do not have to be evenly spaced.

4. In the second column, enter an array of removals, in number of trees per acre,beginning with cell B6. Removals must be 400 trees per acre or less.

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Steep Terrain System

Changing Other Input Data

These are the minimum data entry requirements for the program to run. The data canbe modified if desired. Clicking the Calculate button will run the program and displaythe cost results in the body of the spreadsheet table. You can save the results, modi-fy the input data and resubmit to generate new results, or you can start over againwith a clear spreadsheet by clicking on the Clear button.

Slope, one-way slope skidding/forwarding/yarding distance, and the hourly costs perproductive machine hour (US$/PMH) for each of the different machines can be easilychanged by making entries in the appropriate boxes in the results screen. The num-ber that appears when a change is needed in the hourly costs of one of the machinesis the default value. Once it is changed, the new value becomes the default value forthat session. If the session is saved, the changed value will remain the default valueif that session is reopened.

The average one-way distance is interpreted as either a skidding distance, forward-ing distance, or yarding distance, depending on the harvesting system selected. It is limited to 1,200 feet for cable systems, which corresponds to an external slopedistance of 2,400 feet for rectangular units with parallel corridors. All yarders havephysical upper bounds on yarding distance, based on the line capacities of their drums.

Move-in costs can be a significant portion of the total cost where total removal vol-ume is low. Move-in costs will be included in the results unless the “include” box,under move-in costs, is unchecked. Values for the area harvested and the one-waymove-in travel distance for the equipment can be modified as needed. If the resultshave been previously calculated, be sure to click Calculate again so that the resultswill include the modified move-in costs.

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Figure 3—Window that appears when PPHARVST is opened.

Saving and Printing

Changing the Spreadsheet Calculations (for Advanced Users)

Description of Calculation Spreadsheets

Use the Formula One Workbook Designer to save or print. Double-click on the rightbutton of the mouse while in the spreadsheet portion of the PPHARVST results screento activate the Formula One Workbook Designer. This spreadsheet program offersgreat flexibility; it is compatible with Excel, and its use is similar to Excel.

To save the results and all the assumptions entered, select Write under the file menu.Then choose the preferred format for your new file. Type the file name and extensionin the file name box. Choose from the following:

• Formula One format (vts) if it will be used later in the Formula One WorkbookDesigner

• Excel spreadsheet (xls) if it will be used with Excel

• Tabbed text (txt) for use with another notepad or another word processor. In thiscase, only the spreadsheet from which the command is executed is saved.

The results table can be saved for importation into another program by selecting thattable with the mouse, copying it, then pasting it into a file created by any appropriateWindows application, such as Notepad, another word processor, or a spreadsheet.

The table can be printed from within the Formula One Workbook Designer by choos-ing that option under the file menu.

Exit either application by clicking the X in the upper right corner of the screen.PPHARVST cannot be closed while the Formula One Workbook Designer is active.

If values of internal variables need to be modified, certain harvesting conditionschanged, or calculations of cost or productivity verified, these can be done withPPHARVST by working in the Excel workbook through Formula One. Double-click onthe right mouse button. Then browse or make changes. Save changes by specifyinga vts format and typing in the file name and the vts extension.

The changed workbook also can be saved as an Excel file. In this format, the dataentry and tabular calculation features developed with visual basic and Formula Oneare not available.

The PPHARVST workbook includes five spreadsheets. Four are calculation routines; thefifth is used only to display tabular results.

Flat—Flat contains all data and formulas for the whole-tree and cut-to-length systems.The three most important variables—volume per tree, removals, and yarding distance—are situated in the following cells: C2, C3, and C4, respectively. The values found inthese cells are the values left from the last calculation performed. Any changes to thevalues of these cells will be reflected throughout the spreadsheet. Therefore, if thereis need to change the value of any of those variables, do it only from those cells, andthe productivities of all the machines will correspond to the data entered. The body of the spreadsheet includes the productivity relations for each piece of equipment

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Running a ModifiedVersion of PPHARVST

Conclusions

included in any of the whole-tree or cut-to-length systems. Beginning on line 48, theresults for the whole-tree systems are summarized, with the productivity of eachmachine in 100 cubic feet per hour (ccf/h), its cost per PMH, and finally the cost perccf. The summary of the results for the cut-to-length systems begins on line 61.

Steep—Steep contains all data and formulas for the yarding systems, in similar orderto that in “flat.” Beginning on line 60 is the summary of the partial cut yarding systemwith the productivity of each machine in ccf/h, the corridor change costs, the cost perPMH, and finally the cost per ccf. A similar summary for the clearcut yarding systembegins on line 68; one difference is that line and landing shift costs are includedinstead of corridor change costs. From line 34 to 55, the corridor change, line, andlanding shift costs are explained.

Machine cost—PPHARVST allows the user to change the cost per PMH directly (andshows the default value), but through Formula One, any of the assumptions for para-meters such as machine life, salvage value, and fuel cost per gallon also can bechanged. The parameters are named in the first column of the spreadsheet, and datafor any one machine are listed in the column under the name of that machine.

Move-in cost—The calculations for each component of move-in cost are displayed inthis spreadsheet.

To reload a modified version of PPHARVST, open PPHARVST and Formula One. Then read in the vts file with the version of PPHARVST you want with the File, Readcommand.

The PPHARVST application was developed with machine productivities found in the literature. Machine costs were based on 1996 equipment prices. Selection of studiesand adjustment of productivities were done to make PPHARVST as applicable as possi-ble to ponderosa pine plantations. The PPHARVST model is a general model intendedto be used for broad planning applications. It develops estimates for a limited numberof machines across the range of tree sizes; it estimates for intermediate sizesthrough an interpolation process. This results in a smooth transition of cost over therange of tree sizes and volumes per acre for a particular type of machine configura-tion. It may be necessary to adjust productivity equations or equipment costs to makea reasonable cost estimate for a particular setting with a particular machine. Themodel was not designed for that purpose. The PPHARVST application does not allowestimating of costs beyond those considered reasonable extrapolations of the dataand beyond reasonable limits imposed by machine performance characteristics. Theranges allowed, however, should accommodate most any regime that might be con-templated for management of ponderosa pine plantations with a timber productionobjective. Because the variability in natural stands of mixed species is much greaterthan in ponderosa pine plantations, these cost estimates should not be used forthose types of stands without some corroborating data.

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Literature Cited

Glossary

Hartsough, Bruce R.; Gicqueau, Alex; Fight, Roger D. 1998. Productivity and costrelationships for harvesting ponderosa pine plantations. Forest Products Journal. 48(9): 87-93.

Area harvested—The total area in acres to be harvested by one harvesting systemduring one entry.

Ccf—100 cubic feet.

One-way move-in distance—Distance in miles that equipment is transported toreach the harvest unit.

Operator wage and benefit rate—Total cost per scheduled hour for the operator orcrew.

Skidding/forwarding/yarding distance—This is the skidding distance for thewhole-tree system or the forwarding distance for the cut-to-length system or the yard-ing distance for the cable yarding system. In all cases, it refers to the average (notexternal) one-way distance measured along the slope.

Slope—The average fall-line slope for the harvest unit, measured as a percentage.

Trees/acre—Number of trees per acre being harvested.

Tree volume—Average volume in cubic feet to the merchantable top diameter oftrees being harvested.

Utilization rate—Productive hours divided by scheduled hours.

Vts—Extension applied to Formula One output files.

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Fight, Roger D.; Gicqueau, Alex; Hartsough, Bruce R. 1999. Harvesting costs for management planning for ponderosa pine plantations. Gen. Tech. Rep. PNW-GTR-467. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 8 p.

The PPHARVST computer application is Windows-based, public-domain software used toestimate harvesting costs for management planning for ponderosa pine (Pinus pon-derosa Dougl. ex Laws.) plantations. The equipment production rates were developedfrom existing studies. Equipment cost rates were based on 1996 prices for new equip-ment. Harvesting systems include a cut-to-length harvester-forwarder system, a whole-tree/log-length skidder system, and a skyline cable system. Harvesting costs can be esti-mated for both clearcutting and partial cutting for trees ranging from 3 cubic feet to 250cubic feet. Cost estimates are in U.S. dollars per 100 cubic feet.

Keywords: Costs (logging), logging economics, timber management planning, young-growth stands, ponderosa pine.

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